For years, I had a M380 (the year they came out), 2 405s (the year they came out) and a BD400 (you guessed it, the year they came out). So 4 Excals, all of which were shot a lot. The limb pockets were slightly too small for the limbs, AND, the limbs were not thicker (as the improved limbs are) where they go into the pocket. So, they were being stressed with each cocking (expanding within the limb pocket - into the sharp edges), thus setting up stress fractures. Same with the early Micros.
The fix for the soon to be obsolete Matrix was to file out the interior of the pocket and for the BD was a newly cast riser with slightly larger pocket dimensions. Later, the improved limb design was introduced which stopped expansion in the pocket (thicker in the pocket area) and the way the limb is constructed combined to virtually eliminate limb breakage/splintering. The deflexed limb configuration also contributes to the smoothness (of the BD vs Matrix) of the shot characteristics of the BD. The improved limbs added about 15’/sec over the original limbs. I have more faith in the reliability of the BD line of bows than any other of the Matrix series (at same speed ratings). I expect that the BD series becomes more bullet proof going from the 400 -> 330. The BD series can be best enhanced by having : the new riser design, improved limbs, flemish string and Dr Stirrup string bumpers.
Micro series limbs are under greater stress speed for speed (compared to the Matrix/BD). Even the vaulted HO limbs found their limits , in my opinion, in the 400’/sec ranges. My sample size of 1 (RevX) left me believing Micro sized 400 ratings are somewhat parallel to the Matrix 405 and BD440, maybe, hopefully not as much. I have high hopes that the Hybrid will do well.
Just some thoughts.